1、Designation: F2508 16 An American National StandardStandard Practice forValidation, Calibration, and Certification of WalkwayTribometers Using Reference Surfaces1This standard is issued under the fixed designation F2508; the number immediately following the designation indicates the year oforiginal
2、adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice is intended to establish the procedures forvalidation,
3、 calibration, and certification of walkway tribom-eters.1.2 This practice provides a walkway tribometer supplierwith a procedure and suite of reference surfaces to validate hiswalkway tribometer by properly ranking and differentiating thesurfaces.1.3 This practice provides the user of a walkway trib
4、ometerwith a procedure and suite of reference surfaces to testcalibration of his instrument.1.4 This practice provides a procedure through which anentity may certify a walkway tribometer model, signifying thatthe walkway tribometer model has a completed and docu-mented validation and interlaboratory
5、 study.1.5 This practice describes the necessary materials,specifications, and the cleaning process for reference materials,as well as the requirements for the validation of a supplierswalkway tribometer and calibration of a users walkwaytribometer.1.6 This practice applies to walkway tribometers wi
6、thoutreference to the nature of the scale of the readings produced bythem. The scale used in the reports of validation and calibrationmust be the same, and are to be those of the instrument ordefined for the instrument.1.7 The values stated in SI units are to be regarded asstandard. The values given
7、 in parentheses are for informationonly and are not considered standard.1.8 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine t
8、he applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D1349 Practice for RubberStandard Conditions for Test-ingD3244 Practice for Utilization of Test Data to DetermineConformance with SpecificationsE691 Practice for Conducting an Interlaboratory Study to
9、Determine the Precision of a Test MethodF1646 Terminology Relating to Walkway Safety and Foot-wear3. Terminology3.1 For terms used in this practice not identified herein, referto Terminology F1646.3.2 Definitions:3.2.1 paired t-test, na test of statistical significance basedon the use of students t-
10、distribution and used to compare twosample means (see Annex A2).3.2.2 supplier, nany individual, agent, company,manufacturer, or organization responsible for the walkwaytribometer prior to receipt by the user. D32443.2.3 test foot, nshoe bottom material or surrogatemounted on the walkway tribometer
11、that comes into contactwith the surface being tested.3.2.4 walkway tribometer, nany apparatus used to mea-sure the frictional forces acting at an interface between awalkway surface and shoe material.3.2.4.1 DiscussionA judgement of the adequacy of thesefrictional forces acting on a walkway surface/s
12、hoe surfaceinterface is the basis for an assessment of slip propertiesrelative to human locomotion.3.3 Definitions of Terms Specific to This Standard:3.3.1 calibration, nthe set of operations that establishes,under specified conditions, the relationship between the valuesobtained by a walkway tribom
13、eter and the correspondingsupplier reference values.1This practice is under the jurisdiction of ASTM Committee F13 on Pedestrian/Walkway Safety and Footwear and is the direct responsibility of SubcommitteeF13.10 on Traction.Current edition approved July 1, 2016. Published July 2016. Originally appro
14、vedin 2011. Last previous edition approved in 2015 as F2508 15. DOI: 10.1520/F2508-16.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary
15、 page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.3.2 certification test method, na specific test method thatis used for all walkway tribometer operational tasks in thispractice performed as part of a certific
16、ation.3.3.3 laboratory, na combination of one individual,uniquely identifiable walkway tribometer, one individual,uniquely identifiable test foot, and one operator, none of which(or whom) may be reused for the same purpose in theinterlaboratory study being conducted.3.3.4 reference surfaces (RSs), n
17、specified materials, iden-tified in Section 7, that have an experimentally demonstratedslip properties for a select population of pedestrians and serveas references for walkway tribometer measurements.3.3.5 validation, nthe set of operations that establishes,under specified conditions, the proper ra
18、nking and differentia-tion of reference surfaces by a walkway tribometer.4. Summary of Practice4.1 This practice establishes a procedure to: (1) validatewalkway tribometer models against a human gait-based refer-ence system, (2) calibrate each individual walkway tribometersof a validated model again
19、st published suppliers referencevalues (as defined in 9.1, Eq 4), and (3) certify that thetribometer model has completed a documented validation andinterlaboratory study.4.2 This practice provides for validation and calibration ofwalkway tribometers as a means of verifying their relationshipto refer
20、ence surfaces and verifying a particular device contin-ues to produce consistent results. Certification, if conducted,formally documents the methods, data, and results of avalidation and interlaboratory study.4.3 The method of ranking walkway surface slip propertiesusing a limited population of ambu
21、lating human subjects issupported by a peer-reviewed study.34.4 Validation consists of a series of 24 tests on eachreference surface from this practice. A walkway tribometermodel is considered valid if it ranks the four reference surfacesfrom this practice in the proper order with statistically sign
22、ifi-cant differentiation between results obtained for each surface.Validation is intended to be accomplished for each walkwaytribometer model when it is initially introduced and is to beaccomplished by or on behalf of the supplier and madeavailable to each user.4.5 Calibration for a specific walkway
23、 tribometer requires aseries of 16 tests on each of the reference surfaces from thispractice. A specific walkway tribometer is considered withincalibration if the bias of the mean test values for each surfacefalls within the 95 % confidence interval for the walkwaytribometer model as established by
24、the validation tests (asdefined in 9.1, Eq 4).5. Significance and Use5.1 To be meaningful, walkway tribometer results mustcorrelate the slip characteristics of a surface or contaminant, orboth, to the actual propensity for human slips. To achieve thisgoal, walkway tribometer models must be validated
25、 against astandard with relevance to human ambulation.5.2 This practice prescribes a series of reference surfaceswith known relative slip potential ranging from very high tolow (as defined by laboratory conditions only) upon whichwalkway tribometer models can be validated. The relative slippotential
26、 of each reference surface was established from humansubject walking trials.35.3 The following should be considered in applying thevalidation and calibration obtained by this practice:5.3.1 The scientific study upon which the validation processis based was conducted with a select population of young
27、adults (mean age 26 years) who were free from gait deviationswhile walking in a straight path on a level surface with a meanwalking velocity of 2.18 m/s. This walking velocity is fasterthan the average walking velocity for the general populationwhich includes a much wider age range with greater vari
28、abil-ity; thus, the study sample population of pedestrians andconditions is not representative of the larger general populationof pedestrians.5.3.2 All subjects walked in Oxford-style shoes whose soleswere constructed of smooth styrene butadiene rubber (SBR)with 75A Shore hardness. The shoe style an
29、d sole material isnot representative of all combinations available in the market-place.5.3.3 The reference surfaces defined in this practice are notrepresentative of all walkway surfaces. The outcome of thevalidation practice reflects performance on the type of refer-ence surfaces and surface condit
30、ions defined in this practiceonly. Validation and calibration of a walkway tribometer asdefined by this practice does not imply validation and calibra-tion under all combinations of test foot materials and walkwaysurfaces.5.3.4 The validation and calibration procedure defined bythis practice is not
31、intended to establish a “safe threshold”value for any walkway surface.6. Apparatus6.1 The walkway tribometer shall be free of defects andoperational throughout its range. Refer to the walkway tribom-eter instruction manual to ensure proper operation and instru-ment condition before the validation an
32、d calibration process.6.2 Test Foot Designation and Condition:6.2.1 The supplier must provide test foot material,dimension, storage, and service life specifications. The speci-fications shall be sufficient to permit procurement of anexemplar test foot.6.2.2 A uniquely numbered test foot, meeting the
33、 suppliersmaterial and dimensional specifications shall be provided withthe walkway tribometer being tested.6.2.2.1 The calibration results shall apply only to the walk-way tribometer/test foot combination tested.6.2.3 Prepare the test foot as prescribed by the walkwaytribometer supplier or by a ful
34、ly documented procedure in-cluded in the validation or calibration report.3Powers, C. M., Blanchette, M. G., Brault, J. R., Flynn, J., and Siegmund, G. P.,“Validation of Walkway Tribometers: Establishing a Reference Standard,” Journalof Forensic Sciences, Vol. 55, No. 2, March 2010, pp. 366370.F2508
35、 1627. Reference Surfaces (RSs)47.1 Reference Surfaces:7.1.1 RS APolished black granite whose surface beneaththe test foot is covered with a continuous film of 0.04 % byvolume solution of Triton X-1005(nonionic surfactant) indistilled water (that is, 200 L of Triton X-100 per 500 mL ofdistilled wate
36、r).7.1.2 RS BPorcelain whose surface beneath the test foot iscovered with a continuous film of distilled water.7.1.3 RS CVinyl composition tile whose surface beneaththe test foot is covered with a continuous film of distilled water.7.1.4 RS DCeramic whose surface beneath the test foot iscovered with
37、 a continuous film of distilled water.7.2 Each RS shall be permanently marked to designate itsreference class (that is, “A”, “B”, “C”, “D”).7.3 Reference surfaces shall be stored in a manner thatprevents deformation and contamination.7.4 Reference surfaces should not be used for validation orcalibra
38、tion testing after 5 years from date of purchase.8. Procedure8.1 EnvironmentThe validation and calibration test shallbe performed at a humidity level of 50 6 5 % and atemperature range of 23 6 2C (73.4 6 3.6F) (derived fromPractice D1349).8.2 Reference Surface PreparationThe reference surfaceshall b
39、e free from visible dents, cracks, voids, or othersignificant blemishes.8.2.1 Cleaning:8.2.1.1 No surface treatment except as specified in thissection is permitted.8.2.1.2 Prepare a 0.05 % by volume solution of liquidsodium lauryl sulfate in distilled water (that is, 250 L ofsodium lauryl sulfate pe
40、r 500 mL of distilled water).8.2.1.3 Dip a clean soft-bristled nylon brush in the cleaningsolution and gently scrub in a circular pattern the entirereference surface for a minimum of 10 s. Reapply the cleaningsolution and repeat the minimum 10-s scrubbing two times.8.2.1.4 Rinse the surface thorough
41、ly with distilled water,ensuring that no visible suds or soap residues remain.8.2.1.5 Prepare an ethanol solution containing equal partsdenatured ethanol in distilled water.8.2.1.6 Dip a clean soft-bristled nylon brush, different fromthat used in 8.2.1.3, in the ethanol solution and gently scrub the
42、reference surface for 10 s.8.2.1.7 Dry the reference surface with dry and oil-freecompressed air or air dry if compressed air is not available.Any visible contamination remaining after this step willdisqualify the reference surface for use.8.2.1.8 Ensure that handling of the reference surface doesno
43、t introduce contaminants to the surfaces, including exposingthe surfaces to contact of human skin.8.2.1.9 The cleaning procedure should be performed beforeeach testing session.8.3 Reference Surface MountingMount the reference sur-face onto a flat and rigid substrate that prevents movement ofthe refe
44、rence surface parallel to the test plane of the walkwaytribometer during testing. Select a substrate that will notdeform during wet testing.8.4 Walkway Tribometer Validation TestingUsing thewalkway tribometer being validated and the test foot preparedin 6.2.3, perform 24 tests in accordance with a u
45、niquelyidentifiable version of the walkway tribometer suppliers op-erating instructions or any other formal procedure in the testarea of each of the four reference surfaces that have beenprepared in accordance with 8.2. Of the 24 tests, perform 6 ineach of 4 orthogonal directions, that is, at 0, 90,
46、 180, and 270relative to an arbitrarily defined direction on the referencesurface. Record the results of all tests as specified in Section10.9. Analysis of Results and Walkway TribometerValidation9.1 For the 24 tests on each reference surface, calculate themean X!, standard deviation (SD), standard
47、error (SE)ofthemean, and 95th percentile confidence interval (CI) for thewalkway tribometer test results for each reference surfaceusing Eq 1 through Eq 4, respectively:X51n(i51nxi! (1)where:n = number of measurements (24), andxi= test resultSD 51n 2 1(i51nxi2 xH!2(2)SE 5SD=n(3)95th percentile CI 5
48、X61.96 3SE! 5 X2 1.96 3SE! to X11.963SE! (4)9.2 A valid walkway tribometer must properly rank thefriction between the test foot and reference surfaces andprovide a statistically unique slip resistance measure for eachsurface. A valid walkway tribometer model shall satisfy thefollowing two compliance
49、 criteria:9.2.1 Rank OrderThe rank order of the mean walkwaytribometer results for each reference surface shall be the sameas shown in Annex A1.9.2.2 DifferentiationUsing the mean and standarddeviation, paired t-tests as described in Annex A2 shallproduce significantly different results (p 0.05) for all adja-cently ranked reference surfaces (that is, between RS A and RSB, RS B and RS C, and RS C and RS D).4Available from ASTM International Headquarters. Order Adjunct No.ADJF2508. Original adjunct produced in 2011.5The sole source of su
